Yep, its called the 1988 malicious communication act
http://www.legislation.gov.uk/ukpga/1988/27/contents
"(1)Any person who sends to another person?
(a)a [letter, electronic communication or article of any description] which conveys?
(i)a message which is indecent or grossly offensive;
(ii)a threat; or
(iii)information which is false and known or believed to be false by the sender;
or(b)any [F2article or electronic communication] which is, in whole or part, of an indecent or grossly offensive nature,is guilty of an offence if his purpose, or one of his purposes, in sending it is that it should, so far as falling within paragraph (a) or (b) above, cause distress or anxiety to the recipient or to any other person to whom he intends that it or its contents or nature should be communicated."
Unlike libel/slander, you don't need to put up a bond with this one, so a no-fee,no win ambulance chaser would be more than welcome to take it on.